SLA battery goof-up
I got a couple of 17 Ah sealed lead acid (SLA) batteries from a friend some time ago. Of course I forgot about them for a while and rediscovered them recently. I popped on one of my "smart" SLA two stage chargers to see what happened. Actually, I connected them up and walked away. When I came back later, the little green light was on and I thought, "Great! I'll use those on my next trip!"
Here's a little secret about some of these spiffy little SLA chargers: if the battery voltage is below a certain point, the charger just gives up. So, I wasn't charging these batteries at all. These batteries were dead, dead, dead. I didn't realize this until I had (a) run out and bought new bags to carry them in, and (b) made harnesses for them with inline fuses and PowerPoles. Only then did I realize that one battery was reading 8 volts and the other 2(!) volts. Sigh.
Of course I should have put a voltmeter on these things long before I invested any effort. And, if I were serious about this (and I should be), I would get one of West Mountain Radio's Computer Battery Analyzer (CBA II). A friend has one and swears by it. I should just bite the bullet and get one, too.
In the mean time, I did a cursory web search looking for some cheap Absorbent glass mat (AGM) batteries and found these. The good news is I already have bags and wiring ready when they arrive. I've also got two SLA chargers that will be connected to them trickle charging them constantly. I only need to make that mistake once.
The purpose of these batteries is to give me an opportunity either run nearly forever at QRP levels or even run at 25-30 watts with a larger radio while running portable (like on Georges Island). Of course, at 14 pounds a piece, they chew up my 100 pound budget quickly, but for some trips they'll be well worth it.